tire size GMC SIERRA 2010 User Guide

Light Truck (LT‐Metric) Tire
(A) Light Truck (LT‐Metric) Tire:The United
States version of a metric tire sizing system.
The letters LT as the first two characters in the
tire size means a light truck tire engineered to
standards set by the U.S. Tire and Rim
Association.
(B) Tire Width
:The three‐digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio
:A two‐digit number that
indicates the tire height‐to‐width measurements.
For example, if the tire size aspect ratio is 75, as
shown in item C of the light truck (LT‐Metric) tire
illustration, it would mean that the tire's sidewall is
75 percent as high as it is wide. (D) Construction Code
:A letter code is used to
indicate the type of ply construction in the tire.
The letter R means radial ply construction; the
letter D means diagonal or bias ply construction;
and the letter B means belted‐bias ply
construction.
(E) Rim Diameter
:Diameter of the wheel in
inches.
(F) Load Range
:Load Range.
(G) Service Description
:The service description
indicates the load index and speed rating of
a tire. If two numbers are given as in the example,
120/116, then this represents the load index for
single versus dual wheel usage (single/dual).
The speed rating is the maximum speed a tire is
certified to carry a load.
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Speed Rating:An alphanumeric code assigned
to a tire indicating the maximum speed at which a
tire can operate.
Traction
:The friction between the tire and the
road surface. The amount of grip provided.
Tread
:The portion of a tire that comes into
contact with the road.
Treadwear Indicators
:Narrow bands, sometimes
called wear bars, that show across the tread of a
tire when only 1/16 inch (1.6 mm) of tread
remains. See When It Is Time for New Tires
on
page 6‑82
.
UTQGS (Uniform Tire Quality Grading
Standards)
:A tire information system that
provides consumers with ratings for a tire's
traction, temperature, and treadwear. Ratings are
determined by tire manufacturers using
government testing procedures. The ratings are
molded into the sidewall of the tire. See Uniform
Tire Quality Grading
on page 6‑85.
Vehicle Capacity Weight
:The number of
designated seating positions multiplied by 150 lbs
(68 kg) plus the rated cargo load. See Loading the
Vehicle
on page 5‑30. Vehicle Maximum Load on the Tire
:Load on an
individual tire due to curb weight, accessory
weight, occupant weight, and cargo weight.
Vehicle Placard
:A label permanently attached to
a vehicle showing the vehicle's capacity weight
and the original equipment tire size and
recommended inflation pressure. See “Tire and
Loading Information Label” underLoading the
Vehicle
on page 5‑30.
Inflation - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that under‐
inflation or over‐inflation is all right. It is not.
If your tires do not have enough air (under‐
inflation), you can get the following:
.Too much flexing
.Too much heat
.Tire overloading
.Premature or irregular wear
.Poor handling
.Reduced fuel economy
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If you overfill the tire, release air by pushing on
the metal stem in the center of the tire valve.
Recheck the tire pressure with the tire gage.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out dirt
and moisture.
High-Speed Operation
{WARNING:
Driving at high speeds, 160 km/h (100 mph) or
higher, puts an additional strain on tires.
Sustained high-speed driving causes excessive
heat build up and can cause sudden tire failure.
You could have a crash and you or others could
be killed. Some high-speed rated tires require
inflation pressure adjustment for high speed
operation. When speed limits and road conditions
are such that a vehicle can be driven at high
speeds, make sure the tires are rated for high
speed operation, in excellent condition, and set to
the correct cold tire inflation pressure for the
vehicle load.Vehicles with P265/70R17 or P275/55R20 size tires
require inflation pressure adjustment when driving the
vehicle at speeds of 100 mph (160 km/h) or higher.
Set the cold tire inflation pressure to 3 psi (20 kPa)
above the recommended cold tire pressure shown on
the Tire and Loading Information label.
When you end this high‐speed driving, return the tires
to the cold inflation pressure shown on the Tire and
Loading Information label. See
Loading the Vehicle
on
page 5‑30and Inflation - Tire Pressure on page 6‑72.
Dual Tire Operation
When the vehicle is new, or whenever a wheel, wheel
bolt or wheel nut is replaced, check the wheel nut
torque after 100, 1,000 and 6,000 miles (160, 1 600 and
10 000 km) of driving. For proper torque and wheel nut
tightening information, see Removing the Spare Tire
and Tools on page 6‑92.
The outer tire on a dual wheel setup generally wears
faster than the inner tire. Your tires will wear more
evenly and last longer if you rotate the tires periodically,
see Tire Inspection and Rotation
on page 6‑80. Also
see Scheduled Maintenance on page 7‑3.
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{WARNING:
If you operate your vehicle with a tire that is badly
underinflated, the tire can overheat. An
overheated tire can lose air suddenly or catch fire.
You or others could be injured. Be sure all tires
(including the spare) are properly inflated.
See Inflation - Tire Pressure
on page 6‑72, for
information on proper tire inflation.
Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS) uses radio
and sensor technology to check tire pressure levels.
The TPMS sensors monitor the air pressure in your
vehicle's tires and transmit tire pressure readings to a
receiver located in the vehicle.
Each tire, including the spare (if provided), should be
checked monthly when cold and inflated to the inflation
pressure recommended by the vehicle manufacturer
on the vehicle placard or tire inflation pressure label.
(If your vehicle has tires of a different size than the size
indicated on the vehicle placard or tire inflation pressure
label, you should determine the proper tire inflation
pressure for those tires.) As an added safety feature, your vehicle has been
equipped with a tire pressure monitoring system
(TPMS) that illuminates a low tire pressure telltale when
one or more of your tires is significantly under‐inflated.
Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires as
soon as possible, and inflate them to the proper
pressure. Driving on a significantly under‐inflated tire
causes the tire to overheat and can lead to tire failure.
Under‐inflation also reduces fuel efficiency and tire
tread life, and may affect the vehicle's handling and
stopping ability.
Please note that the TPMS is not a substitute for proper
tire maintenance, and it is the driver's responsibility to
maintain correct tire pressure, even if under‐inflation
has not reached the level to trigger illumination of the
TPMS low tire pressure telltale.
Your vehicle has also been equipped with a TPMS
malfunction indicator to indicate when the system is
not operating properly. The TPMS malfunction indicator
is combined with the low tire pressure telltale. When
the system detects a malfunction, the telltale will
flash for approximately one minute and then remain
continuously illuminated. This sequence will continue
upon subsequent vehicle start‐ups as long as the
malfunction exists.
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The low tire pressure warning light may come on in cool
weather when the vehicle is first started, and then turn
off as you start to drive. This could be an early indicator
that the air pressure in the tire(s) are getting low and
need to be inflated to the proper pressure.
A Tire and Loading Information label, attached to your
vehicle, shows the size of your vehicle's original
equipment tires and the correct inflation pressure for
your vehicle's tires when they are cold. SeeLoading the
Vehicle
on page 5‑30, for an example of the Tire and
Loading Information label and its location on your
vehicle. Also see Inflation - Tire Pressure on page 6‑72.
Your vehicle's TPMS can warn you about a low tire
pressure condition but it does not replace normal tire
maintenance. See Tire Inspection and Rotation
on
page 6‑80and Tires on page 6‑64.
Notice: Liquid tire sealants could damage the Tire
Pressure Monitor System (TPMS) sensors. Sensor
damage caused by using a tire sealant is not
covered by your warranty. Do not use liquid tire
sealants.
TPMS Malfunction Light and Message
The TPMS will not function properly if one or more of
the TPMS sensors are missing or inoperable. When the
system detects a malfunction, the low tire warning light
flashes for about one minute and then stays on for the
remainder of the ignition cycle. A DIC warning message
is also displayed. The low tire warning light and DIC
warning message come on at each ignition cycle until
the problem is corrected. Some of the conditions that
can cause the malfunction light and DIC message to
come on are:
.One of the road tires has been replaced with the
spare tire. The spare tire does not have a TPMS
sensor. The TPMS malfunction light and DIC
message should go off once you re‐install the road
tire containing the TPMS sensor.
.The TPMS sensor matching process was started
but not completed or not completed successfully
after rotating the vehicle's tires. The DIC message
and TPMS malfunction light should go off once the
TPMS sensor matching process is performed
successfully. See “TPMS Sensor Matching
Process” later in this section.
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You need new tires if any of the following statements
are true:
.You can see the indicators at three or more places
around the tire.
.You can see cord or fabric showing through the
tire's rubber.
.The tread or sidewall is cracked, cut, or snagged
deep enough to show cord or fabric.
.The tire has a bump, bulge, or split.
.The tire has a puncture, cut, or other damage that
cannot be repaired well because of the size or
location of the damage.
The rubber in tires degrades over time, even if they are
not being used. This is also true for the spare tire,
if your vehicle has one. Multiple conditions affect how
fast this aging takes place, including temperatures,
loading conditions, and inflation pressure maintenance.
With proper care and maintenance tires will typically
wear out before they degrade due to age. If you are
unsure about the need to replace your tires as they get
older, consult the tire manufacturer for more information.
Buying New Tires
GM has developed and matched specific tires for your
vehicle. The original equipment tires installed on your
vehicle, when it was new, were designed to meet
General Motors Tire Performance Criteria Specification
(TPC spec) system rating. If you need replacement
tires, GM strongly recommends that you get tires with
the same TPC Spec rating. This way, your vehicle will
continue to have tires that are designed to give the
same performance and vehicle safety, during normal
use, as the original tires.
GM's exclusive TPC Spec system considers over a
dozen critical specifications that impact the overall
performance of your vehicle, including brake system
performance, ride and handling, traction control, and tire
pressure monitoring performance. GM's TPC Spec
number is molded onto the tire's sidewall near the tire
size. If the tires have an all‐season tread design, the
TPC spec number will be followed by a MS, for mud
and snow. See Tire Sidewall Labeling
on page 6‑65for
additional information.
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GM recommends replacing tires in sets of four (or six if
your vehicle has dual rear wheels). This is because
uniform tread depth on all tires will help keep your
vehicle performing most like it did when the tires were
new. Replacing less than a full set of tires can affect
the braking and handling performance of your vehicle.
SeeTire Inspection and Rotation
on page 6‑80for
information on proper tire rotation.
{WARNING:
Mixing tires could cause you to lose control
while driving. If you mix tires of different
sizes, brands, or types (radial and
bias-belted tires) the vehicle may not handle
properly, and you could have a crash. Using
tires of different sizes, brands, or types may
also cause damage to your vehicle. Be sure
to use the correct size, brand, and type of
tires on your vehicle's wheels.
{WARNING:
If you use bias-ply tires on the vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel
could fail suddenly, causing a crash.
Use only radial-ply tires with the wheels
on the vehicle.
If you must replace your vehicle's tires with those that
do not have a TPC Spec number, make sure they are
the same size, load range, speed rating, and
construction type (radial and bias‐belted tires) as your
vehicle's original tires.
Vehicles that have a tire pressure monitoring system
could give an inaccurate low‐pressure warning if
non‐TPC Spec rated tires are installed on your vehicle.
Non‐TPC Spec rated tires may give a low‐pressure
warning that is higher or lower than the proper warning
level you would get with TPC Spec rated tires. See Tire
Pressure Monitor System on page 6‑75.
Your vehicle's original equipment tires are listed on the
Tire and Loading Information label. See Loading the
Vehicle
on page 5‑30, for more information about the
Tire and Loading Information label and its location on
your vehicle.
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Different Size Tires and Wheels
If you add wheels or tires that are a different size than
your original equipment wheels and tires, this could
affect the way your vehicle performs, including its
braking, ride and handling characteristics, stability, and
resistance to rollover. Additionally, if your vehicle has
electronic systems such as anti‐lock brakes, rollover
airbags, traction control, and electronic stability control,
the performance of these systems can be affected.
{WARNING:
If you add different sized wheels, your vehicle
may not provide an acceptable level of
performance and safety if tires not recommended
for those wheels are selected. You may increase
the chance that you will crash and suffer serious
injury. Only use GM specific wheel and tire
systems developed for your vehicle, and have
them properly installed by a GM certified
technician.
See Buying New Tires
on page 6‑83andAccessories
and Modificationson page 6‑4for additional
information.
Uniform Tire Quality Grading
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA
Temperature A
The following information relates to the system
developed by the United States National
Highway Traffic Safety Administration (NHTSA),
which grades tires by treadwear, traction, and
temperature performance. This applies only to
vehicles sold in the United States. The grades are
molded on the sidewalls of most passenger car
tires. The Uniform Tire Quality Grading (UTQG)
system does not apply to deep tread, winter-type
snow tires, space-saver, or temporary use
spare tires, tires with nominal rim diameters of
10 to 12 inches (25 to 30 cm), or to some
limited-production tires.
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Tire Chains
{WARNING:
If your vehicle has dual wheels or P265/65R18,
P275/55R20 or LT265/70R17 size tires, do not
use tire chains. They can damage your vehicle
because there is not enough clearance. Tire
chains used on a vehicle without the proper
amount of clearance can cause damage to the
brakes, suspension, or other vehicle parts. The
area damaged by the tire chains could cause you
to lose control of your vehicle and you or others
may be injured in a crash.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer's
instructions. To help avoid damage to your
vehicle, drive slowly, readjust, or remove the
device if it is contacting your vehicle, and do not
spin your vehicle's wheels.
If you do find traction devices that will fit, install
them on the rear tires.Notice:
If your vehicle does not have dual
wheels and has a tire size other than P265/65R18,
P275/55R20 or LT265/70R17, use tire chains only
where legal and only when you must. Use chains
that are the proper size for your tires. Install them
on the tires of the rear axle. Do not use chains on
the tires of the front axle. Tighten them as tightly as
possible with the ends securely fastened. Drive
slowly and follow the chain manufacturer's
instructions. If you can hear the chains contacting
your vehicle, stop and retighten them. If the contact
continues, slow down until it stops. Driving too fast
or spinning the wheels with chains on will damage
your vehicle.
If a Tire Goes Flat
It is unusual for a tire to blowout while you are driving,
especially if you maintain your vehicle's tires properly.
If air goes out of a tire, it is much more likely to leak out
slowly. But if you should ever have a blowout, here are
a few tips about what to expect and what to do:
If a front tire fails, the flat tire creates a drag that pulls
the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
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3. Assemble the wheel blocks (B) and jack (G)together with the wing nut (A) and retaining
bolt (H).
4. Position the jack (G) in the mounting bracket (F). Position the holes in the base of the jack (G) onto
the pin in the mounting bracket (F).
5. Return them to their original location in the vehicle. For more information, refer to Removing the Spare
Tire and Tools
on page 6‑92for more information.
Spare Tire
Your vehicle, when new, had a fully-inflated spare tire.
A spare tire may lose air over time, so check its inflation
pressure regularly. See Inflation - Tire Pressure
on
page 6‑72and Loading the Vehicleon page 5‑30for
information regarding proper tire inflation and loading
your vehicle. For instruction on how to remove, install or
store a spare tire, see Removing the Flat Tire and
Installing the Spare Tire
on page 6‑97and Storing a
Flat or Spare Tire and Tools on page 6‑106. Notice:
If the vehicle has four-wheel drive and the
different size spare tire is installed on the vehicle,
do not drive in four-wheel drive until you can have
your flat tire repaired and/or replaced. You could
damage the vehicle, and the repair costs would not
be covered by your warranty. Never use four-wheel
drive when the different size spare tire is installed
on the vehicle.
Your vehicle may have a different size spare tire than
the road tires originally installed on your vehicle. This
spare tire was developed for use on your vehicle, so it
is all right to drive on it. If your vehicle has four-wheel
drive and the different size spare tire is installed, keep
the vehicle in two-wheel drive.
After installing the spare tire on your vehicle, you should
stop as soon as possible and make sure the spare tire
is correctly inflated. Have the damaged or flat road tire
repaired or replaced as soon as you can and installed
back onto your vehicle. This way, the spare tire will be
available in case you need it again.
Do not mix tires and wheels of different sizes, because
they will not fit. Keep your spare tire and its wheel
together. If your vehicle has a spare tire that does not
match your vehicle's original road tires and wheels
in size and type, do not include the spare in the
tire rotation.
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